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TOMITA, Shinsuke (JSPS Fellow)
Agroecology

Research Interests

In Northeast Thailand, where rainified paddy cultivation is commonplace, direct dry seeding is replacing transplanting to increase the frequency of successful plantings and to save on labor costs. My research is on the impact of this change on paddy vegetation from an agricultural and an ecological viewpoint. A large number of paddy fields with a wide range of climatic, topographic, soil and hydrological conditions were studied area. My research revealed that direct dry-seeded fields are resource poor and have a wider range of water conditions within a field due to a rougher soil surface than transplanted fields. This results in lower productivity of total vegetation for rice growing in direct dry-seeded fields. However, weed productivity was not significantly different between the direct dry seeding and transplanted fields. Direct dry-seeded fields have more species-rich vegetation and greater diversity than the transplanted fields. Previous planting methods for particular fields did not influence productivity and diversity of paddy vegetation. I concluded that the use of direct dry seeding increased biomass production of rice and the diversity of the paddy vegetation. The results also suggest that key concepts of the analytic framework to be used to harmonize agricultural production and biodiversity are thought to identify resource availability and disturbance intensity. All these led me to construct a model simultaneously explaining both rice production and biodiversity from disturbance intensity and resource availability in rainfed paddy fields.

Current research topic:

Research Activities in 2005 Fiscal Year

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